Question 3: a. According to the given usage scenario give main success scenario, alternative extensions, and special requirements. -Cashier: Wants accurate, fast entry, and no payment errors, as cash drawer short- ages are deducted from his/her salary. - Salesperson: Wants sales commissions updated. - Customer: Wants purchase and fast service with minimal effort. Wants easily visible display of entered items and prices. Wants proof of purchase to support returns. - Company: Wants to accurately record transactions and satisfy customer interests. Wants to ensure that Payment Authorization Service payment receivables are recorded. Wants some fault tolerance to allow sales capture even if server compo- nents (e.g. remote credit validation) are unavailable. Wants automatic and fast update of accounting and inventory. - Manager: Wants to be able to quickly perform override operations, and easily debug Cashier problems. - Government Tax Agencies: Want to collect tax from every sale. May be multiple agen- cies, such as national, state, and county, - Payment Authorization Service: Wants to receive digital authorization requests in the correct format and protocol. Wants to accurately account for their payables to the store b. Draw activity diagram for the given scenario